Energetic beam processes utilize tools that generate, focus, and direct beams comprised of energetic particles, for example, photons, ions, electrons and/or accelerated neutral particles, to modify and/or analyze the surface of the specimen. Such modifications can include creating a topography at a surface. The topography of a surface can be described in terms of locations at the surface (e.g. represented by “x” and “y” positional coordinates) and the relative height or depth (e.g. “z”) of the local surface at those locations. Energetic beam processes can be “additive” in that they add material to a surface, such as in laser thermal chemical vapor deposition, photochemical deposition, electron or ion induced chemical vapor deposition. Energetic beam processes can also be “subtractive” in that they remove material from a surface, such as focused ion beam milling, laser ablation, photochemical etching, sputtering and laser thermal etching.
Disclosed are methods and apparatuses whereby an interferometer, integrated with an energetic particle column, is used to monitor and provide feedback control of the depth, shape and/or roughness of features created at the surface of a specimen by energetic beam processes. The methods and apparatuses disclosed are suitable for specimens including planar, multi-planar, faceted, curved, irregular surface profiles and blind holes and, can be practiced in vacuum, atmospheric pressure and/or at pressures higher than atmospheric pressure.